1. Field of the Invention
This invention relates to remote controllers of the type used to control VCRs, TVs, cable boxes and satellite receivers, and in particular relates to universal remote controllers that can control a variety of appliances.
2. Description of the Related Art
Universal remote controllers are available that provide the capability to mimic a number of different remote controllers. This allows the user to use one universal remote controller rather than have a separate remote controller for each appliance, such as one for a television and another one for the VCR and another one for the cable box. One conventional implementation of a universal remote controller includes a learn function key that is pushed to put the universal remote controller into the learn mode. While in the learn mode, the universal remote controller can learn the IR codes for each key on another remote controller, such as a remote controller for a VCR. The user pushes a key on the remote controller and a corresponding key on the universal remote controller and then the IR pulses that are transmitted from the remote controller are detected by an IR receiver on the universal remote controller and then are stored in the universal remote controller into a battery backed random access memory (RAM). This is repeated for all of the individual keys. Then when a key is pushed on a universal remote controller the IR code that has been learned from the other remote controller is retrieved from RAM and transmitted via an IR transmitter on the universal remote controller.
Another technique in the conventional art is to provide a programmer that can load the universal remote controller with the IR codes for various appliances.
For example, in the Darbee U.S. Pat. No. 5,228,077 there is disclosed a universal remote controller that can operate a variety of appliances. The Darbee universal remote controller includes a RAM which can store code data and instructions for generating codes for operating appliances. The instruction codes and code data are loaded into the RAM, which allows for infinite upgradability of the universal remote control. The code data in Darbee includes the on and off times for each IR code for the appliances to be controlled.
The Darbee patent discloses a data transmission system for coupling the universal remote controller through a modem to a telephone line, or through a television set to a television signal picked up by the television set. The data that is downloaded to the universal remote controller is the instruction code and the code data.
Another example of a universal remote controller is Ehlers, U.S. Pat. No. 4,626,848, which discloses a reconfigurable remote controller which has the ability to learn, store and repeat remote control codes from any other IR transmitter. Such a reconfigurable remote controller device includes an IR receiver, a microprocessor, a non-volatile random access memory, a scratch pad random access memory, and an IR transmitter. The Welles II, U.S. Pat. No. 4,623,887 is similar to the Ehlers patent. Another universal remote controller in the prior art is Evans, et al., U.S. Pat. No. 4,825,200, which teaches a reconfigurable remote control transmitter that includes a learn mode and a run mode and is similar to the remote control system disclosed in the Ehlers patent. Imoto, U.S. Pat. No. 4,771,283, teaches a system for collecting operating codes from various remote controllers by inputting the code data therefrom via IR code signals to an IR receiving diode at the input of the system, deciphering these code signals, storing them in a RAM and then upon operation of keys, supplying outputs via one of several cables extending to devices to be controlled.
In all of the previous universal remote controllers the entire IR code is essentially downloaded to the universal remote controller either via IR transmission or via telephone or via a television signal. Once the entire IR code, or data corresponding to the IR codes such as on and off times are stored in the universal remote controller RAM, then the user accesses this data by pressing keys on the universal remote controller, which sends commands to the appliances. If many appliances are to be controlled, the amount of the storage in the RAM can become excessive. Thus, it is desirable to provide a universal remote controller that does not need to store entire IR codes related to each individual key of each remote controller to be mimicked.